1. Field of the Invention
The present invention relates to a hand-held power tool such as, e.g., a chisel or combination hammer and including a pneumatic percussion mechanism defining a central percussion axis and having a guide tube, a driving member reciprocating in the guide tube, a percussion member driven by the driving member, and an air spring located between the driving member and the percussion member for transmitting a reciprocating movement of the driving member to the percussion member, a motor for driving the percussion mechanism, a motor-driven elongate swashplate member for reciprocating the driving member, and an adjustment device for adjusting a displacement stroke of the driving member which is determined by a swashplate angle.
2. Description of the Prior Art
German Publication DE 32 05 141 A1 discloses a hand-held power tool formed as an electrically driven hammer drill including an air cushion percussion mechanism driven by a swashplate member of a swashplate drive. The percussion mechanism includes a driving member such as, e.g., a driving piston displaceable in a guide tube and axially reciprocated a swashplate member. The driving member drives, via the air cushion or the air spring, a percussion member likewise displaceable in the guide tube and which imparts blows, via an anvil, to a working tool receivable in a tool holder provided in the front of the power tool. For adjusting a maximal stroke path of the driving member, a swashplate angle of the swashplate member is adjusted in three steps by an adjustment device that is formed as a step-by-step switching device. To this end, a hub member of the swashplate member is pivotally adjusted on a supporting member relative thereto by adjustment of a swashplate angle and is formlockingly connected with the supporting member in its respective relative pivotal position by coupling elements, with the supporting member being mounted on an intermediate shaft at an acute angle. With the step-by-step switching device, an axial displacement of the intermediate shaft is converted in a stepwise rotary adjustment of the hub member for changing the swashplate angle.
The drawback of the solution of the German Publication DE 32 05 141 A1 consists in that the step-by-step switching device can be actuated only when the hand-held power tool is switched off. Moreover, the step-by-step switching device is constructively very expensive.
Accordingly, an object of the present invention is to provide a hand-held power tool of the type discussed above and in which the above-discussed drawbacks of the known power tool are eliminated.